1. Field of the Invention
This application relates to heterocyclic compounds and more particularly to herbicidally active substituted thiadiazine-5-,thiazole-4-, and thiazoline-4-acetic acid derivatives obtained from the reaction of ethyl 4-chloroacetoacetate with thiosemicarbazide.
2. Description of the Prior Art
Thiosemicarbazide has previously been condensed with alpha-halocarbonyl compounds resulting in the formation of a variety of five and six member heterocyclic isomers. Thus, the reaction of phenacyl bromide or chloroacetone has been disclosed to produce a thiazole, a thiazoline, or a thiadiazine. However, it has been extremely difficult to characterize the structures that are produced.
Although the prior art is aware of the reaction of such alpha halogen carbonyls with thiosemicarbzide, its reaction with gamma--halogencarbonyls is unknown although the reaction of gamma--haloketo esters with thiourea has been disclosed to yield ethyl 2-aminothiazole-4-acetate, a compound of no disclosed utility.
The prior art has thus not taught the condensation of thiosemicarbazide with ethyl-4-chloroacetoacetate much less that the products of such reaction include a wide variety of different compounds and ring configurations having selective utilities or that reaction control and direction may be exerted by the reaction solvents and conditions employed. Moreover, the prior art has not taught the preparation of derivatives of these materials by benzoylation and or nitrosation to obtain ring rearrangements and exocyclic double bonds yielding still further novel herbicidal compounds.
Accordingly, a primary object of this invention is to obtain new heterocyclic condensation products of thiosemicarbazide and ethyl 4-chloroacetoacetate under varying conditions of acidity, solvent polarity and temperature.
Another object is to obtain further active materials by selectively neutralizing, dehydrating, benzoylating, and/or nitrosating the condensation products of the character described.